Most injuries of the cervical spine are soft tissue injuries, and not vertebral fractures. The accident victims with soft tissue injuries have been known to have residual pain for many years after the accident. The overall objective of the proposed research is to provide a better understanding of the mechanisms of these injuries to the cervical spine caused by sudden acceleration/deceleration of the head with respect to the trunk, the so called whiplash injuries. The available research studies have used whole cadavers, anthropometric dummies, and mathematical models to simulate the injury-causing events. The traumatic event is studied from outside and not at the site of injury in the cervical spine. The uniqueness of the proposed research lies in its ability to directly study the site of injury during the trauma. Fresh cadaveric specimens (occiput to T1) will be utilized. The specimen is provided with a simulated headpiece. The trauma is produced in a specially constructed apparatus where the acceleration at the base of the specimen, the T1 vertebra, is simulated to be similar to that documented in real life rear-end car crashes. Radiographs are taken and multidirectional instability measurements are conducted before the trauma and immediately after. The trauma is documented by measuring the loads at the base of the specimen, accelerations of the headpiece, movements of the vertebrae, and deformations of the ligaments, muscles, and arteries. After the trauma, the specimen is carefully dissected, and injuries to the various soft tissues and bone are quantified. Studies are conducted when the head is in the midsagittal plane and when the head is rotated and side-bent to simulate the more complex real life situations. Correlations will be established between the input accelerations and several output measures: quantified injuries, multidirectional instabilities, and radiographic measurements. The significance of the research lies in a better understanding of the mechanisms of whiplash injuries and, specifically, in the: prevention of these injuries by designing optimal automotive seats and sports equipment; diagnosis of the injuries by developing radiographic tests that are more sensitive to documenting the soft tissue injuries; and, treatment by better assessment of the anatomic injuries and multidirectional instabilities of the cervical spine.